<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>

<body>

</body>

<script>
  //js数据类型：
  //基本数据类型：Number String Boolean Null Undefined Symbol
  //引用数据类型：Array Object Function
  //如何检测?
  console.log(typeof [1, 23])
  console.log(typeof { name: '123' })
  console.log(typeof function a123() { })

  console.log(typeof '123')
  console.log(typeof 123)
  console.log(typeof true)
  console.log(typeof null)
  console.log(typeof undefined)
  console.log(typeof  Symbol)

console.log([1, 23] instanceof Array) //true
console.log(Array.isArray([1, 23])) //true
console.log(Symbol instanceof Object)//true

</script>

</html>